In my garage I have surface mounted metal switch and outlet boxes with conduit running to the attic. All these boxes have metal covers. On another forum I saw posted the following: "NECA 1-2006, 6.k) Covers for outlet boxes shall be of a type designed, intended and appropriate for the use and location, and have suitable corrosion protection. Plastic device plates shall not be used as covers for surface mounted boxes."

I like my metal boxes and their raised covers, but I want to replace a switch or two with a Wi-Fi enabled smart switch or outlet. My garage does not have a strong Wi-Fi signal. I thought I might replace the metal covers with plastic so as to block less of the signal. I don't have an NEC code book and do not have good knowledge of the code, but the above quoted section of code seems to rule out this solution. Is the above a specific situation?

Perhaps "device plates" are not the same as purpose made covers (like the raised metal ones I have now)? Are there covers, purpose made for surfaces boxes, that are made of a material that won't block Wi-Fi signals but will meet NEC requirements?

  • Think it is because plastic covers to easy to break if out in the open. Maybe think about some type of wifi extender.
    – crip659
    Jun 25, 2022 at 19:11
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    They are also very ill-fitting for drawn steel boxes intended for surface mount. I snag my clothing on them every time I walk by, I swear. Really you should use 4x4 boxes with domed covers. Let the large Decora opening be your WiFi window, and get a WiFi booster. Jun 25, 2022 at 23:39
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    I'd assume (hope) there's no plastic SM cover plates. But after you add an old-work box next to it, you can put w/e you want. Still leaves the problem of the wifi being shit in the garage, and now there's a switch somewhere weird. Look into if plastic covers are permissible on raceway; I don't see why they wouldn't be. - "I like my metal boxes and their raised covers" ... then you're going to be super disappointed with square-ass raceway. - Final answer: no. Decide what you're going to transition to, as this boils down to a Q of esthetics. Where the best answer for that is mesh.
    – Mazura
    Jun 26, 2022 at 0:10
  • Is the NEC rule in my question really about using a cover / plate that might overhang the sides of the box rather than the material the cover is made from? I see handy boxes, designed for surface mounting, with plastic covers. I could certainly find metal covers designed for flush mounted boxes but would not use them on a surface mounted box. I don't have a code book so do not know the context (if needed) for this NEC rule. Could someone comment on this part of the code as to its scope?
    – user152764
    Jun 27, 2022 at 15:20

1 Answer 1


I would recommend to use WiFi extender

Rather then messing with outlets and covers and CODE,

If you need more WiFi signal in the garage, get a WiFi extender.

It plugs in any socket, and you can experiment the best one for it, inside the home or in the garage.

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